DESCRIPTION (from applicant's abstract): Studies are proposed to further define the capacity of opioid agonists to modulate host-pathogen interactions during infection. Certain opioids act to alter the replication of HIV-1 in infected cells. Opioids also exert a significant impact on expression of critical chemokines and chemokine receptor genes and have the capacity to regulate both the trafficking of immune cells to sites of infection, as well as the regulation of chemokine receptors, which serve as critical HIV-1 co-receptors. The working hypothesis is that the opioid induced increase in HIV-1 replication can be reversed by natural cellular antiviral defense mechanisms, i.e., the 2', 5'-oligoadenylate synthetase (2-5OAS)/RNase L and p68 kinase (PKR) pathway. Our studies will evaluate the impact of opioids on the antiviral pathways of target cells and define the capacity of opioids to modulate the expression of critical cytokines/cytokine receptors. It is proposed: (1) To determine the anti-HIV-1 effects of metabolically stable, non-toxic a 2-5A derivative on PBMC and monocytes isolated from the blood of HIV-1 positive intravenous drug users (IVDU), as well as normal donors and HIV-1-infected non-IVDU. In addition, studies will be conducted to determine the ability of a 2-5A derivative to inhibit replication of primary isolates of HIV-1 from HIV-1-positive IVDU using viral isolates from both therapy-naive and HAART-resistant patients. HIV-1 replication levels will be correlated with the expression of critical cytokines and chemokine receptors. (2) To determine the consequences of expression of the antiviral genes, 2-5OAS and PKR, on opioid-potentiated HIV-1 replication in T cells and monocytes transduced with HIV-1-LTR-driven 2-5OAS/PKR constructs. These studies will employ established cell lines as well as primary T cells and macrophages derived from CD34+ cord blood hematopoietic progenitor stem cells. Intracellular immunization will be utilized to determine the effects of opioids on HIV-1 replication and cytokine/cytokine receptor expression in cells with constitutive expression of mu, kappa, and delta-opioid receptors. (3) To determine the effects of opioids on cytokine/cytokine receptor expression and reactivation of HIV-1 reservoirs in latently infected T cell and monocyte lines that have been transduced with HIV-1 LTR-driven 2-5OAS/PKR constructs. Overall, these studies should provide strategies to control HIV-1 replication and cellular mobilization/uptake of the virus.